The present invention relates to methods by which to deposit high-K films, and more particularly to semiconductor devices which incorporate therein a high-K layer.
A continuing trend in semiconductor technology is to build integrated circuits with more and/or faster semiconductor devices. The drive toward this ultra large-scale integration (ULSI) has resulted in continued shrinking of devices and circuit features. As the devices and features shrink, new problems are discovered that require new methods of fabrication and/or new arrangements.
One such problem associated with semiconductor devices which incorporate therein one or more high-K layers is carbon contamination due to the use of organic precursors to form high-K layers. For example, a high-K layer of hafnium oxide can be deposited using the following method. Hafnium is supplied in the form of a hafnium-containing vapor or gas such as hafnium tetra-t-butoxide and the oxygen is supplied in the gaseous form. In this method, the hafnium tetra-t-butoxide and oxygen gas are supplied to an appropriate CVD apparatus to form a layer of hafnium oxide having a desired thickness.
During the process of forming a hafnium oxide layer carbon from the remaining portion of the hafnium-containing vapor or gas (hafnium tetra-t-butoxide) can contaminate the hafnium oxide layer. One unwanted side effect of such contamination is that the carbon contamination has to be removed by oxidation to ensure a reliable high-K film is produced. The oxidation process to remove the carbon contaminates in the high-K layer also results in a high-K layer with an increased thickness compared with the thickness of a corresponding standard-K layer, and an increased equivalent oxide thickness (EOT).
Hence, there is a need in the art for a method which permits the growth of high-K layers without the need for an oxidation step to remove carbon contaminates therefrom.
In one embodiment, the present invention relates to a process for fabricating a high-K layer comprising the steps of: placing a semiconductor substrate into a first chamber of a deposition apparatus; supplying high-K precursors to the deposition apparatus; generating ions or molecules of high-K material from the high-K precursors in a second chamber of the deposition apparatus, the second chamber being remote from the first chamber; passing the ions or molecules of high-K material from the second chamber to the first chamber; and depositing a high-K layer upon the semiconductor substrate.
In another embodiment, the present invention relates to a process for fabricating a semiconductor device which contains a high-K layer comprising the steps of: placing a semiconductor substrate into a first chamber of a deposition apparatus; supplying high-K precursors to the deposition apparatus; generating ions or molecules of high-K material from the high-K precursors in a second chamber of the deposition apparatus, the second chamber being remote from the first chamber; passing the ions or molecules of high-K material from the second chamber to the first chamber; depositing a high-K layer upon the semiconductor substrate; and subjecting the semiconductor substrate to further process steps in order to yield a semiconductor device.
In another embodiment, the present invention relates to a process for fabricating a layer in a semiconductor device comprising the steps of: placing a semiconductor substrate into a first chamber of a deposition apparatus; supplying layer forming precursors to the deposition apparatus; generating ions or molecules of the layer forming precursors in a second chamber of the deposition apparatus, the second chamber being remote from the first chamber; passing the ions or molecules of the layer forming precursors from the second chamber to the first chamber; and depositing a layer upon the semiconductor substrate.
In one embodiment, the previously mentioned layer in a semiconductor device deposited via the present invention comprises at least one compound selected from silicon, silicon oxide, silicon dioxide, silicon oxynitride, silicon nitride, silicon germanium, or mixtures thereof In another embodiment, the previously mentioned layer in a semiconductor device deposited via the present invention layer comprises at least one metal or metal containing compound selected from copper, gold, silver, aluminum, tungsten, tantalum, molybdenum, cobalt, nickel, titanium, ruthenium, rhodium, platinum, palladium, metal oxides thereof, metal nitrides thereof, alloys thereof, or mixtures of two or more thereof.
In yet another embodiment, a method according to the present invention can be utilized to co-deposited a layer of a semiconductor device with one or more dopants. Such dopants include, but are not limited to, nitrogen, oxygen, germanium, silicon germanium, phosphorus or arsenic.
Thus, the present invention overcomes the problems associated with carbon contamination of high-K layers via the use of molecular deposition. Additionally, the present invention also permits the control of metal to oxygen ratios, if applicable, in high-K materials.